A considerable and continuous need exists for (1) a pharmaceutical composition comprising an antiviral drug, for (2) a controlled release dosage form comprising the pharmaceutical composition, and for (3) a method for treating a virus infection by administering an antiviral drug composition to a patient in need of antiviral therapy.
The need exists for dispensing means including a pharmaceutical composition and for a dosage form because during the past years various antiviral chemotherapeutic drugs were synthesized for treating virus infections, while concomitantly the dispensing art did not provide a pharmaceutical composition and dosage form for dispensing the antiviral drug to a patient in need of antiviral therapy. For example, the antiviral compound 9-(2-hydroxy-ethoxymethyl)-guanine, also known as acyclovir, possesses potent antiviral activity, is available for treating herpes virus, yet acceptable means are not available for dispensing this drug to a patient in need of it. This antiviral drug and other antiviral drugs exhibit poor aqueous solubility and thus do not lend themselves for formulating into a pharmaceutical composition for subsequent dispensing from a dosage form. That is, generally this physical-chemical property severely limits antiviral drug formulation fluid during operation of the dosage form.
In the light of the above presentation, it will be appreciated by those versed in the antiviral art, to which this invention pertains, that a demand exists for a pharmaceutical composition and for a dosage form that can deliver a difficult to deliver antiviral drug at a known and controlled rate to a patient in need of antiviral therapy. The demand exists for an oral composition and dosage form that can deliver an antiviral drug at a controlled rate and at a constant dose per unit time. The demand exists for dispensing means for gastrointestinal delivery of antiviral drugs for obtaining antivirus hemodynamic effects that are free of fluid wash-out, and substantially independent of the variable environment of the gastrointestinal tract. It will be appreciated further by those versed in the antiviral art that if a novel and nonobvious antiviral composition and dosage form are provided, they would represent an advancement and valuable improvement in the antiviral therapeutic art.